US2174318A - Unit tank heater - Google Patents

Description

Sept. 26, 1939. G. T. ELLIS p pm UNIT TANK HEATER Filed April 14, 1936 2 Shams-5mm 1 Sept. 26, 1939. G. T. ELLIS 2,174,313

UNIT TANK HEATER Filed April 14, 1936 2 Sheets-Sheet 2 i 5 2 O Q. 5: I 7 i i I 2.? i i L as" 5.7.7.5211? Patented Se t. 25, 1939 2,174,318

UNITED STATES PATENT OFFICE UNIT TANK HEATER- Guy '1'. Ellis, Louisville, Ky minor to am Vogt Machine 00., Louisville, Ky., a corporation of Kentucky Application April 14, 1936, Serial No. 14,365 i 9 Claims. (Cl. 257-198) This invention relates to unit tank heaters in- Figure 4 is a longitudinal section through one tended to be installed in large storage tanks for end oia steam tube; viscous liquids, and designed for the localized Figure 5 is a modified form of the invention in heating, in the region of the point of withdrawal, which the steamcore is employed in a horizontal '5 of only approximately the quantity of the liquid heater for general heat exchanging purposes; 5' which is to be withdrawn, for the purpose of re Figure 6 is a section taken along the line 5-6 ducing its viscosity sufilciently to facilitate drawof Figure 5; 7 ing it off. Figure 7 is a longitudinal section through the Heaters of this type are known and may comend of one of the steam tubes; prise a shell extending into the tank having an Figure 8 is a section taken along the line 8--8 l0 open'inner end for receiving the viscous liquid of Figure 7; V and containing a steam coilfor heating the liquid Figure 9 is a longitudinal section through a as it passes through the shell. The suction side vertical type of heat exchanger; and

of a discharge pump opens into the opposite end Figure 10 is a cross section taken along the of the shell. I lino iii-40 of Figure 9. 15

In previous tank heaters of the type described, Referring now in detail to the several figures the steam coils have included return bends at and first adverting to that form of the invention their outer ends, which have the effect of a series illustrated in Figures 1 to 4, the numeral l repreof bars across the mouth of the shell, obstructing sents the wall of a storage tank adapted to conthe entrance of the viscous liquid into the shell, tain a body of viscous liquid such, for example, 20 with the result that the pump could not be worked as crude oil. A unit tank heater which is, in gento its full capacity due to drawing a vacuum at eral, designated by the reference character 2, is its induction end. mounted at the side of the tank and extends One of the objects of the present invention is through the wall I as shown. The tank comthe provision in an open ended unit tank heater pr es a sh ll 3 wh ch in the i l r x mp 25 of a system of steam tubes which make individual has an open inner end 4 terminating in a plane end presentation toward the open inner end of inclined to the axis of the heater so as to give the the shell, whereby to minimize their obstructiveopen end a lar Cross Sect onal area than it v m ss to fr e flow into said shell. would if the shell terminate in a plane perpen- Another object of the invention is to provide in dicular to the axis of the heater, although t e 30 a heater of the class described, a shell, the open last named Construction is Within the p v end of which terminates in a plane inclined to the of the invention. The outer end of the shell 3 axis of the shell, for making thearea of the open m y be fl n s at 5 n n t the flan e and greater than its dametrical cross section. Tests a tube Sheet 5 Carrying a bundle o sp e at Still another object of the invention is the parallel, o d ended, outer tubes 1 which exemployment of a steam coil with the individual tend into the shell 3, pref y at least throughend presentation feature in combination with out its length- AS Shown, the u es extend bemodified forms of shell for general purposes of 31 the plane of e inner pen nd, but While heat exchange without reference to the immerthis s a v t geous in Warming the liq jus sion of the heater in a body of liquid for the local- Prior to its entry into the pe a d of the shell, ized heating of the same. it is not essential.

Other objects of the invention will appear as The tube Sheet 5 may be bOlted 0 t e flan e 5 the following description of a preferred and so that by removing the bolts equ valent 5&- practical-embodiment th f proceeds curing means the tube sheet with the attached I In the drawings throughout the Several figures bundle of tubes may be withdrawn from the shell 45 of which the same characters of reference have for inspection This of f can only P been employed to designate identical parts: done when the storage tank empty to pomt Figure 1 is a longitudinal section through a below the level of the heater A flan ed extension 8 is made unitar ith t unit tank heater embodying the principles of the tube i 6 in any suitable manner g, '5

Present mvfmtloni ing, and a tube sheet 9 is detachably secured to Fi ur 2 1s a r s seetwn t n along the lme the flanged extension 8 and carries a bundle of 2-2: of Figure 1; open ended inner tubes Iii of smaller external Figure 3 1s a cross section taken along the line diameter than the internal diameter of the outer 3-3 of Figure 1 showing the tube supports: tubes and extending partially therethrough, but

terminating short of the closed ends of the outer tubes. The ends of the inner tubes adjacent the tube sheet I open into a common chamber Ii formed within an enclosing head I 2 bolted together with the tube sheet I with the flanged extension I. By removing the bolts the head l2 may betaken oil, exposing the open ends of the inner tubes which may be thus readily inspected. If necessary, the tube sheet [together .with the bundle of inner tubes it may be drawn out from the shell and from the outer tubes. 1.

It is thus apparent that by this simple construction all parts of the heater may be disassembled for inspection or repair.- The head i2 has an inlet connection l3 adapted to be connected to a source of steam while the chamber within the extension 3 and between the two tube abeets,'which chamber is open to the outer tubes I, is provided with a connection it for the discharge. of the exhaust steam and condensate. Steam passes through the inner tubes ill, issues as a Jet from the inner open ends of the inner tubes into the terminal portions of the outer tubes and returning, it passes through the annular space between the inner and outer tubes discharging into the chamber within the extension 3. By this arrangement any condensate in the outer tubes is continuously blown out and the tubes are thus at all times 100% eflicient. The viscous liquid from the storage tank enters the open end of the shell 3, is warmed by contact with, and proximity to the steam pipes and is drawn out by way of the connection ii to which is connected the induction side of a pump, not

It is old in the art to have a unit tank heater in which tubes corresponding to the steam tubes I are Joined adjacent the open end of the shell bytransverse portions or return bends, but Figure 4 shows that the outer tubes I of the present invention are individually closed at their inner ends II and that the inner ends are preferably either rounded or streamlined so as to present the minimum resistance to the admission of viscous liquid from the storage tank to the shell. Figure 4 shows that the closed ends of the outer tubes are preferably thickened so as to withstand the wear and tear incident to the impingement oi steam from the inner tubes against said inner ends.

In that form of the invention illustrated, by reason of the inclined oblique terminal plane of the open end of the shell 3 and the fact that the steam tubes extend the full length of said shell, said tubes are in part exposed beyond the limits of the shell so that they impart heat to and reducethe viscosity of the liquid outside of the shell and adjacent the open end thereof preparing it for easy entry into said shell under the pull of the pump. The individual end presentation of the steam tubes 1 minimizes the obstruction created by the presence of the steam pipes still facilitating the inflow of the liquid. Both of these factors together with the enlarged .area afforded by the inclined shape of theopen end of the shell permits a large capacity pump to be employed without the development of suction at the induction end than is practicable with known forms of unit tank heater.

The tubes 1 are supported within the shell by transverse straps I1 preferably of undulating shape as shown secured at their ends to a ring R slidably fitting within the shell 3. Said straps are provided at intervals of two tiers of tubes and there are two such series of straps as shown *drical halves, the upper extension in Figure 1 with the straps staggered so as to minimize the obstruction of the straps to the flow of liquid.

It will be understood, of course, that the purpose of a unit tank heater in a storage tank is to heat only the amount of liquid withdrawn instead of heating the entire body of liquid in the storage tank which was the practice prior to the advent of the unit tank heater.

Referring now to that form of the invention shown in Figure 5, the construction may be identical with that already described insofar as the header i2, tube sheets 9 and 3 and the respective bundles of inner and outer steam tubes l0 and I are concerned. The shell, however, is closed at its outer end it and a connection ll provided at the outer end for the admission of the liquid to be heated. Within the shell 3 are a plurality of babies 23 and 2| secured alternately to the upper and lower walls of the shell so that the entering liquid must follow a tortuous course from the outer to the inner end of the shell sweeping the sides of the steam tubes 1 and thus being subjected in its traverse of the heater to the maximum degree of heat transfer. The baiiies and 2| are maintained perpendicular to the axis of the shell by means of tie rods 22 extending from the tube sheet 6 to the final baiile at the outer end of the heater. The tie rods pass through perforations in the battles and support spacers 23 of larger diameter than said perforations and which abut against opposite sides of the baiiles.

Figure 9 shows a modification of the invention adapted for general heat exchanging purposes between two liquids, in which the shell 24 is vertically mounted and The and outer tubes i0 and 1 carried thereby, may

be identical with corresponding elements in those forms of the invention already described. The shell 24 is tiered serially upon two extensions 26 and 21. The extension 26 has supporting brackets 28 projecting radially therefrom adapted to rest upon concrete supports, and an underlying head 29 is provided forming a chamber into which the inner tubes l0 open. The space within the extension 26 and between the two tube sheets forms a chamber communicating with the outer tubes. A vertical partition 30 divides the shell 24 into two semi-cylindrical halves, excepting near the top of the shell where the partition 30 terminates short of the upper end of the shell forming an over-pass for the liquid circulating in the shell outside of the tubes. An inlet 32 and an outlet 33 are provided at the bottom of the shell 24 on opposite sides of the partition.

The partition 30 continues through the extension 21 to the tube sheet 8, and a continuation 3i of the partition. passes through the extension 26 terminating at the tube sheet 9. Thus, likewise, both extensions are divided into two semi-cylin- 21 registering with the halves of the shell 24, while the partition in extension 26 separates the inner tubes in and outer tubes 1 into two serial banks. The extension 21 is provided with an inlet 32 and an outlet 33.

In operation, one of the liquids, in heated state, for example, enters the inlet 32, circulates upwardly in the right hand part of the shell, flows over the overpass downward through the left hand half of the chamber within the shell 24 and discharges through the outlet 33. The other liquid enters an inlet 34 on the left side of the 15 lower extension, circulates through the outer tubes 1 of the right hand bank and returns through the inner tubes ill of the same bank discharging into the header 29 which acts as an underpass directing the liquid to the inner tubes ID of the right hand bank through which it flows upwardly, discharging into the outer tubes, and downwardly through the outer tubes into the right hand chamber of the lower extension 26 from which it discharges through the outlet .35.

It will be understood from the above that there is a counter-current circulation in both'sides of the shell between the liquids which are in heat exchanging relation and that part of the liquid which is in the shell 24 of highest temperature is in heat interchanging relation with liquid in the tubes of highest temperature while liquid in the shell of lower temperature is in heat exchanging relation with liquid in the tubes of lower temperature, thus at all times maintaining the rate of heat exchange between the two liquids substantially constant.

What I claim is:

1. Immersion type heater comprising a shell, a bundle of spaced steam tubes within said shell extending toward the inner end thereof, said inner end having an opening of such size as to fully expose the end of said tube bundle, said tubes being closed, and unconnected at their inner ends, whereby to provide a minimum aggregate obstructive area to the inflow of liquid into the inner end of said shell, the latter having an outlet adjacent its outer end adapted to be connected to the induction side of a discharge pump.

2. Immersion type heater comprising a shell, a bundle of substantially parallel rectilinear spaced steam tubes within said shell extending toward the inner end thereof, said inner end having an opening of such size as to fully expose the end of said tube bundle, said tubes being closed, and unconnected at their inner ends whereby to provide an obstructive area notgreater than their aggregate cross sectional area, to the inflow of liquid into the inner end of said shell.

3. Immersion type tank heater comprising. a shell the bounding side wall of which terminates in a slope extending downwardly and away from the outer end of said shell, a bundle of spaced steam tubes within said shell extending toward the inner end thereof, intersecting the plane of said slope whereby the end of the tube bundle and length portions of the upper tubes are fully exposed to the exterior of said shell, said tubes being closed and unconnected at their inner ends whereby to provide a minimum aggregate obstructive area to the inflow of liquid into the inner end of said shell, said shell having an outlet adjacent its outer end adapted to be connected to the induction side of a discharge pipe.

4. Immersion type tank heater comprising a shell the bounding side of which terminates in a slope extending downwardly and away from the outer end of said shell, a bundle of spaced steam tubes within said shell extending toward the inner end thereof, intersecting the plane of said slope and terminating in a plane perpendicular to the longitudinal axisof said shell, the

end of the tube bundle and length portions of the upper tubes being fully exposed to the exterior of said shell, said tubes being closed, and unconnected at their inner ends whereby to provide an obstructive area t6 the endwise inflow of liquid into the inner end of said shell not greater than the aggregate cross sectionalarea of said tubes, said shell having an outlet adjacent its outer end adapted to be connected to the induction side of a discharge pump.

5. Immersion type heater comprising ashell, a bundle of spaced steam tubes within said shell extending toward the inner end thereof, said inner end having an opening fully exposing the end of said tube bundle, said tubes being closed, and unconnected at their inner ends whereby to provide a minimum aggregate obstructive area to the inflow of liquid into the inner end of said shell, the latter having an outlet adjacent its outer end adapted to be connected to the induction side of a discharge pump, said tubes each comprising an inner and an outer member, the inner ends of the outer members being closed and the inner ends of the inner members being open to provide return circulation through said tubes, spaced tube sheets at the outer end of said shell, one supporting the outer members and the other the inner members, one set of members opening into the chamber between said tube sheets.

6. Immersion type of heater as claimed in claim 5, the tube sheets being independently removable from said shell unitarily with the respective sets of tube members which they support.

'7. Immersion type heater comprising a shell, a bundle of substantially parallel, rectilinear steam tubes within said shell extending toward the inner end thereof, said inner end having an opening of such size as to fully expose the end of said tube bundle, said tubes being closed and unconnected at their inner ends whereby to provide a minimum aggregate obstructive area to the inflow of liquid into the inner end of said shell, the latter having an outlet adjacent its outer end adapted to be connected to the induction side of a discharge pump, said tubes each comprising an inner and an outer member, the inner ends of the inner members being open .to provide return circulation through said tubes, spaced tube sheets at the outer end of said shell, one supporting the inner and the other the outer set of tube members, one set of said members opening into the chamber between the tube sheets.

8. Immersion type heater comprising a shell, a bundle of spaced steam tubes within said shell extending toward the inner end thereof, said inner end having an opening of such size as to fully expose the end of said tube bundle, said tubes being closed and unconnected at their inner endswhereby to provide a minimum aggregate obstructive area to the inflow of liquid into the inner end of said shell, the latter having an outlet adjacent its outer end adapted to be connected to the induction side of a discharge pump, said tubes each comprising an inner and an outer member, the inner ends of the outer members being closed and the inner ends of the inner members being open, to provide return circulation through said tubes, spaced tube sheets at the outer end of said shell respectively supporting the inner and outer sets of'tube members, one set of tube members communicating with the chamber formed between said tube sheets, a header for said shell, the other set of tube members communicating with the chamber within said header, means for supplying steam to one of said chambers and a steam and condensation outlet for the other of said chambers.

9. Immersion type tank heater as claimed in claim 8, said header and said tube sheets being separately removable from said shell, and said tube sheets being unitarily removable with the respective sets of tube members which they support.

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